Method of forming a dual in-line package

Abstract

A lead frame assembly of indefinite length having a pair of spaced parallel carrier strips, collapsible rungs extending between the strips at regular intervals along the length of the assembly and a number of leads extending inwardly from the opposed edges of the strip between the rungs are collapsed inwardly to seat the ends of the leads against the sides of circuit modules previously positioned between the ends of the leads. The lead ends are seated in recesses in the circuit modules and are subsequently soldered to metalized surfaces on the modules. Following the bending of the leads, the carrier strips and rungs are cut away.

What I claim as my invention is: 
     
       1. The method of forming a dual in-line package from a unitary lead frame having spaced parallel carrier strips with groups of leads extending toward each other from the strips and rungs joining the strips between opposed groups of leads and a circuit module having opposed contact surfaces comprising the steps of: A. freely positioning a circuit module between adjacent rungs on the lead frame with the contact surfaces of the module adjacent the ends of the leads on the carrier strips;   B. moving the carrier strips toward the circuit module to foreshortened the adjacent rungs and seat the ends of the leads on both carrier strips against the contact surfces on the circuit module, and then;   C. forming bonded electrical connections between the lead ends and the contact surfaces on the circuit module.   
     
     
       2. The method of claim 1, including the step of deforming the foreshortened rungs to retain the lead ends seated against their respective contact surfaces. 
     
     
       3. The method of claim 1, wherein the carrier strips and leads are flat and including the step of moving the carrier strips toward each other and deforming the adjacent rungs away from the rest of the lead frame. 
     
     
       4. The method of claim 3, including the step of crimping portions of the adjacent rungs together to retain the lead ends seated against the contact surfaces. 
     
     
       5. The method of claim 4, including the step of soldering the lead ends to the contact recesses. 
     
     
       6. The method of continuously forming lead frame assemblies through the use of an indefinite length of lead frame having spaced parallel carrier strips with groups of leads extending toward each other from opposite strips and rungs joining the strips between opposed groups of leads and circuit modules having opposed contact surfaces, including the steps of: A. moving the lead frame along a work path;   
     
     
       B. Positioning modules between adjacent rungs on the lead frame so that the modules are carried downstream with the lead frame by the adjacent upstream rungs; C. moving the carrier strips to either side of the circuit modules toward each other as the modules and lead frame are moved downstream to bring the ends of the leads between the adjacent rungs into engagement with the contact surfaces on the circuit modules and at the same time foreshortening the adjacent rungs; and   D. forming bonded electrical connections between the leads and the contact surfaces on the circuit modules.   
     
     
       7. A method as in claim 6, including the step of piloting the ends of leads into contact recesses in the circuit modules during movement of the circuit module downstream by the upstream rung and then seating the leads into the recesses in the circuit module and thereby moving the module away from the upstream rung.